KR19990005035U - Arm Cylinder Speed Control of Excavator - Google Patents

Abstract

The present invention relates to an arm cylinder speed control device of an excavator, and the first and second pumps (1,2) and the first and second pumps (1,2) to supply the pressure oil to the arm cylinder (5) The first and second directional switching springs 3 and 4 having ports formed so that the hydraulic oil drained from the arm cylinder 5 is drained through only one of the springs when the cylinder 5 is operated in one direction. A pilot pump 13 for supplying pilot pressure oil for manipulating two-way switching springs 3 and 4 and a hydraulic oil drained from the arm cylinder 5 when the arm cylinder 5 is operated in one direction. A first pilot pressure passage (6a) having a regenerative select valve (9) and connected to one side hydraulic pressure portions (3a, 4a) of the first and second direction switching springs (3,4); A second pilot pressure passage 6b connected to the other side pressure receiving portion 3b of the first direction switching spring 3; The branch pilot pressure passage 6c branched from the second pilot pressure passage 6b and connected to the other pressure receiving portion 4b of the second direction switching spring 4 and the one side pressure receiving portion of the regeneration select valve 9. ) And; And a select valve 11 installed in the branch pilot pressure passage 6c to selectively block the flow passage 6c to selectively throttle the hydraulic oil drained from the arm cylinder 5, and the driver needs to By switching the selector valve 11 in accordance with the above, the oil pressure discharged from the second pump 2 is supplied to or disconnected from the arm cylinder 5 so that the arm crowd operation can be selected at a high speed or a low speed.

Description

An apparatus for controlling the arm cylinder speed in an excavator

The present invention relates to an arm cylinder speed control device of an excavator, and more particularly, to an arm cylinder speed control device of an excavator that enables the operator to adjust the working speed of the arm by adjusting the operating flow rate supplied to the arm cylinder.

In general, excavators are equipped with a boom attached to the upper swing body mounted so as to pivot about the lower body, and the boom is installed so that the arm can be deflected, and the bucket for excavating at the tip of the arm can also be deflected. The boom, the arm and the bucket are adapted to be operated on the boom cylinder, the arm cylinder and the bucket cylinder, respectively, for operating them.

In general, an excavator is provided such that the boom cylinder, the arm cylinder and the bucket cylinder, as well as almost all actuators provided in the excavator are supplied from one hydraulic source and operated by pressure oil distributed from the main control valve block.

Here, the arm operation of the excavator, as shown in Figure 2, the pressure oil discharged from the first pump 101 is passed to the arm cylinder 103 via the first direction switching spring 102 for the arm cylinder of the main control valve block. It is supplied and made by expansion and contraction of this arm cylinder 103.

In addition, the first direction switching spring 102 is switched operation by selectively adjusting the supplied pressure oil discharged from the auxiliary pump 104 to the joystick 105, the dump operation during the arm operation is the arm cylinder This is done by retracting 103, and arm crowding is done by stretching the arm cylinder 103. As shown in FIG.

And as shown in FIG. 3 in the middle of an arm crowd operation as mentioned above. When the bucket 106 and the arm 107 are located in the right zone with the vertical solid line as shown in FIG. 4, the direction of movement of the arm cylinder 103 and the direction of the acting load W are the same. The load is generated, and thus the speed at which the arm cylinder 103 moves by the load W due to its own weight or the like is faster than the pressure oil pressure supplied from the pump 101, so that the pressure corresponding to the speed at which the arm cylinder 103 moves is increased. The drawback was that the oil could not be supplied and cavitation occurred.

In the related art, a regenerating device is installed in the first direction switching spring 102 to compensate for insufficient pressure oil in the arm cylinder 103 to prevent cavitation.

In this regeneration apparatus, as shown in FIG. 2, the drain flow path 108 and the supply flow passage 109 of the pressurized oil formed in the first directional switching spring 102 communicate with each other via the regeneration flow passage 110. The regeneration flow path 110 is selectively opened and closed by a regeneration select valve 112 installed in the tank side drain line 111 connected to the drain flow path 108 to replenish the insufficient pressure oil in the arm cylinder 103. The regenerative select valve 112 is controlled by a pilot signal pressure Pi of a pilot line 114 branched from the head side pressure oil supply line 113.

Then, in order to speed up the arm crowd operation, conventionally, the pressure oil discharged from the second pump 115 operated in parallel to the first pump 101 passes through the second direction switching spring 116 for controlling another actuator. The oil is discharged from the first direction switching spring 102 and is supplied to the arm cylinder 103.

However, in the related art, since the first and second direction switching springs 102 and 116 are interlocked and switched according to the operation of one joystick 105, the operator has no choice but to select only a high speed operation, and also by a minute amount of regeneration amount. There was a problem in that it was not possible to select and perform low-speed tasks that did not require high-speed operations, while sufficiently preventing cavitation.

Therefore, the present invention was devised to solve the above problems, and the arm cylinder speed control device of the excavator, which allows the operator to work the arm crowd at low or high speed by adjusting the amount of oil flowing into the arm cylinder as needed. The purpose is to provide.

The present invention for achieving the above object. The first and second pumps, and the first and second pumps to supply the pressure oil to the arm cylinder, the port is formed so that the pressure oil drained from the arm cylinder when the arm cylinder is operated in one direction is drained through any one of the sprue only A pilot pump for supplying pilot pressure oil for controlling the first and second direction switching springs, the first and second direction switching springs, and the hydraulic oil drained from the arm cylinder when the arm cylinder is operated in one direction. An arm cylinder speed control device of an excavator having a regeneration select valve, comprising: a first pilot pressure passage connected to one side hydraulic part of the first and second direction switching springs; A second pilot pressure passage connected to the other pressure receiving portion of the first direction switching spring; A branch pilot pressure passage branched from the second pilot pressure passage and connected to the other pressure receiving portion of the second directional switching spring and to the one pressure receiving portion of the regeneration select valve; It is characterized in that it further comprises a select valve installed in the branch pilot pressure flow path to selectively block the flow path to selectively throttle the pressure oil drained from the arm cylinder.

According to the present invention made as described above, when the arm cylinder is extended to the arm cylinder operation, the driver is to switch the operation of the select valve, supply or shut off the pressure oil discharged from the second pump to the arm cylinder, extending the arm cylinder You can choose to work at high or low speeds with the Armcrown operation, either at high or low speed.

1 is a hydraulic circuit diagram of the arm cylinder speed control device of an excavator according to the present invention,

2 is a hydraulic circuit diagram of a device for adjusting the arm cylinder speed of an excavator according to the prior art;

Figure 3 is an operating state of the arm for explaining the arm operation of the excavator,

Figure 4 is a schematic hydraulic circuit diagram for explaining the principle of cavitation occurs in the arm crowd operation.

Explanation of symbols on the main parts of the drawings

1,2: 1st, 2nd pump 3, 4: 1st, 2nd direction switching spring

5: arm cylinder 6a, 6b: pilot line

7: oil tank 8: drain line

9: regeneration select valve 10: regeneration flow path

11: Select valve 12: Joystick

13: pilot pump 14: spring

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a hydraulic circuit diagram for explaining the arm cylinder speed control device of the excavator according to the present invention.

As shown in the present invention, the pressurized oil discharged from the first and second pumps 1 and 2 passes through the first and second direction switching springs 3 and 4, respectively, and then is joined to the arm cylinder 5. When the arm cylinder 5 is operated in one direction, a port is formed such that the pressure oil drained from the arm cylinder 5 is drained through only one of the splines, and the first direction switching springs 3 and 4 ) And a regeneration select valve (9) is installed in the drain line (8) connecting the oil tank (7). When the arm cylinder (5) is operated in one direction, the drain line (8) is throttled to change the first direction. Cavitation of the arm cylinder 5 is prevented by communicating or blocking the regeneration flow path 10 formed in the spun 3.

In addition, a first pilot pressure passage is connected to one side hydraulic parts 3a and 4a of the first and second direction switching springs 3 and 4, and the other hydraulic part of the first direction switching spring 3 is connected. A branch connected to the second pilot pressure passage 6b at 3b and connected to the other hydraulic part 4b of the second directional switching spring 4 and one hydraulic part of the regeneration select valve 9. A pilot pressure passage 6c branches off from the second pilot pressure passage 6b, while a select valve 11 is provided in the branch pilot pressure passage 6c to selectively select the branch pilot pressure passage 6c. By blocking the pressure oil drained from the arm cylinder (5) to selectively throttle.

Here, the select valve 11 is a solenoid valve. When the select valve 11 is operated in a direction of blocking the select valve 11, the second direction switching spring 4 is switched to a neutral position and the second pump 2 The pressure oil discharged from the < RTI ID = 0.0 > 1) < / RTI > blocks the supply to the arm cylinder 5, and the regeneration select valve 9 lowers the pressure of the drain line 8, thereby regenerating the first direction switching spring 3. It is possible to reduce the amount of oil pressure regenerated through the oil passage 10,

Referring to the process of adjusting the arm speed according to the arm speed cylinder control device of the excavator of the present invention made as described above are as follows.

First, the pilot pressure oil discharged from the pilot pump 13 is operated by operating the joystick 12 in the direction in which the arm cylinder 5 is extended to perform the arm crowd operation in the state in which the select valve 11 is in communication. In other words, the first direction switching spring 3 is switched to the left in the drawing, the second direction switching spring 4 is switched to the right in the drawing, and the pressure discharged from the first and second pumps 1 and 2 Oil is passed through the first and second direction switching springs (3,4) and then joined and fed to the arm cylinder (5). The expansion speed of this arm cylinder 5 is made fast.

Accordingly, in the state where the select valve 11 is in communication with each other, the arm cloud operation performed by the expansion of the arm cylinder 5 can be performed at high speed.

Here, when the select valve 11 communicates as described above, the regenerative select valve 9 is switched in the direction in which the spring 14 is compressed to throttle the pressure oil drained from the drain line 8 to the oil tank 7. Accordingly, the line pressure of the drain line 8 before passing through the regeneration select valve 9 is raised to drain the cylinder from the cylinder 5 through the regeneration flow path 10 of the first direction switching spring 3. By regenerating the pressurized oil, it is possible to prevent the cavitation of the cylinder 5.

On the other hand, when the selector valve 11 is switched in the direction in which the internal flow path is blocked, and the joystick 12 is operated in the direction in which the arm cylinder 5 is extended, the pilot signal pressure is changed in the first direction switch. It acts only on the pools 3 and 4 and does not act on the second direction switching spring 4.

Accordingly, the first direction switching spring 3 is switched to the left in the drawing and the second direction switching spring 4 is in a neutral position, and the arm cylinder 5 is discharged from the first pump 1. By only supplying the pressurized oil. The expansion speed of the arm cylinder 5 becomes slower than when the pressure oil discharged from the second pump 2 joins and is supplied, and as a result, the arm crowd operation is performed slowly.

Therefore, when the select valve 11 is cut off, the arm crowd operation | work made by extension of the arm cylinder 5 can be selected at low speed.

Here, when the select valve 11 is blocked as described above, the regenerative select valve 9 is switched in the direction of restoring the spring 14, and the pressure oil drained through the first direction switching spring 3 is not throttled. Since it is drained to the oil tank 7 as it is, only a small amount can be regenerated through the regeneration flow path 10, so that relatively little cavitation can be prevented during low speed operation.

According to the arm speed control device of the excavator according to the present invention as described above, by supplying or blocking the pressure oil discharged from the second pump to the arm cylinder by communicating or blocking the select valve to increase the expansion speed of the arm cylinder Alternatively, by being able to operate at a low speed, the operator can obtain the effect of performing the arm crowd work while selecting the high speed or the low speed as needed.

Claims (1)

The first and second pumps (1 and 2) and the hydraulic cylinder from the first and second pumps (1 and 2) are supplied to the arm cylinder (5), but the arm cylinder (5) is operated in one direction. 5) a pie for manipulating the first and second direction switching springs 3 and 4 and the first and second direction switching springs 3 and 4 formed with a port such that the hydraulic oil drained from 5) is drained through only one of the springs. An arm of an excavator having a pilot pump 13 for supplying a lot pressure oil and a regeneration select valve 9 for throttling pressure oil drained from the arm cylinder 5 when the arm cylinder 5 is operated in one direction. In the cylinder speed regulator, A first pilot pressure passage 6a connected to one side hydraulic parts 3a and 4a of the first and second direction switching springs 3 and 4; A second pilot pressure passage 6b connected to the other side pressure receiving portion 3b of the first direction switching spring 3; The branch pilot pressure passage 6c branched from the second pilot pressure passage 6b and connected to the other pressure receiving portion 4b of the second direction switching spring 4 and the one side pressure receiving portion of the regeneration select valve 9. ) And; The excavator further comprises a select valve 11 installed in the branch pilot pressure passage 6c and selectively blocking the flow passage 6c to selectively throttle the hydraulic oil drained from the arm cylinder 5. Arm cylinder speed control.